This invention relates in particular to a device for washing a combinational weighing machine of a kind with a plurality of article-supplying troughs and weigh hoppers. More broadly, the invention relates to combinational weighing machines equipped with such a washing device.
As disclosed in Japanese Patent Publication Tokkai 63-30725, for example, combinational weighing machines are used for the purpose of gathering several pieces of articles with individually fluctuating weights such as candies, fruits and vegetables such that their total weight will be equal to, or very close to a specified target weight. FIG. 9 shows an example of such a combinational weighing machine, indicated generally by numeral 1 and having a conveyor 12 for dropping articles to be weighed to the center of a dispersion feeder 2. A plural number of supply troughs 3 are arranged around the periphery of the dispersion feeder 2. Each supply trough 3 can be vibrated by a vibrator 3a associated with it so as to deliver the articles received from the dispersion feeder 2 at one of its ends to corresponding one of pool hoppers 4 at the other of its ends. Each pool hopper 4 is provided with a gate 5 and has a weigh hopper 6 associated with it situated below it. Each weigh hopper 6 is provided with a weighing device 7 and a gate 8, and there is a collector chute 9 below the gates 8 of the weigh hoppers 6. Weight values of articles outputted from the weigh hoppers 6 are variously combined to determine a particular combination such that the sum of its weight values is equal to, or satisfactorily close to a predetermined target weight. As shown in FIG. 10, each gate 5 or 8 of the hopper 4 or 6 is adapted to be opened and closed by means of a pushing member 10 which moves backward and forward and thereby serves to push one end 11a of a linking mechanism 11 for the gate 5 or 8.
The inner surfaces of the supply troughs 3 and the hoppers 4 and 6 of the weighing machine 1, as shown in FIG. 9, must be cleaned whenever vegetables, for example, of a different kind are going to be weighed because they are where the articles to be weighed come into contact. It has been a customary routine, therefore, to remove the supply troughs 3 and the hoppers 4 and 6 from the weighing machine 1 and transport them to a separately provided washing device to have them cleaned therein. Since most combinational weighing machines use many supply troughs and hoppers, it is a cumbersome process to remove them and install them again.
In view of the above, Japanese Patent Publication Tokkai 2-161324, for example, disclosed a cleaning device which does not require the troughs or the hoppers to be removed from the weighing machine but washes them while they remain installed. According to this prior art technology, use is made of a rotary arm adapted to move around the weighing machine and a cleaning liquid and/or warm water is emitted from a nozzle on this rotary arm. As a result, the emitted liquids are scattered around, adversely affecting the sanitary conditions of the near-by working areas as well as the packaging machine which is likely to be set beneath the weighing machine.